Process for storing digitally coded video synchronous sound signals through time compression by duplicating sound data during recordation

ABSTRACT

A process for storing picture synchronous sound signals is provided. The sound signals are divided into segments for this purpose, whose cycle is equal to the cycle of the associated video signal segments. In addition to the sound data of the actual video signal segment each sound signal segment also includes one portion of the sound data of the preceding video signal segment and the subsequent video signal segment. The sound signal segments are time compressed to the length of the video signal segments for recording or transmitting. The sound signals can be softly changed over due to overlapping during backplay and cutting.

STATE OF THE ART

The invention is based on a process for storing of digitally coded videosynchronous sound signals in accordance with the type of the main claim.A process for interference signal free assembly of two digitally codedsignal segments is already known from DE-OS 32 33 287, in particular ofsound signals which are associated with television picture scenes. Withthe known process it is possible to changeover picture synchronous soundsignals in discrete time cycles, preferably in the range of between twohalf or full pictures without any intermediary stage. However, for thispurpose it is required that alternating scanned values or pairs ofscanned values must be recorded alternately in at least two channels,and that the transmission for the scanned values of the first soundsignal occurs at different time intervals in the different recordingchannels with respect to the scanned values of the second sound signal.Within the changeover interval which is defined by the actualtransmission of the significance of the data of the signal segment to begated out is changed from a nominall value to a minimal value and thesignificance of the data of the signal segments to be gated in arechanged from a minimum value to a nominal value.

A playback device for pulse code modulated signals (PCM-signals) is alsoknown from DE-OS 30 32 673 which is provided with an editing circuitwhich expands the PCM-signal trains beyond the intended cutting locationwith the assistance of delays. Thereby, the PCM-signal trains arealternately supplemented with correcting signals and the output signalsof the first PCM-pulse train is brought from a large significance Xl toa small significance XO and the data of the second PCM-pulse train froma small significance XO to a large significance Xl with the assistanceof multiplication circuits. Accordingly, the signals characterized bythe first PCM-pulse train are gated out in the area of the cuttinglocation and the signals which are characterized by the second pulsetrain are grated in at the same area of the cutting edge.

ADVANTAGES OF THE INVENTION

In contrast thereto, the process in accordance with the invention forstoring digitally coded picture synchronous sound signals with thecharacterizing features of the main claim is advantageous in that thesound signals from the PCM- pulse train to be gated out as well as thePCM-pulse train of the sound signals to be gated in are availablewithout a two channel recording in the area of any given cuttinglocation between two half or full pictures. A further advantage is thatthe location of the sound recording is not displaced with respect to thelocation of the video recording, even during a repeated cutting editing,so that the required lip synchronisation is maintained.

Advantageous further embodiments and improvements of the process statedin the main claim are possible due to the measures stated in thesubclaims. It is particularly advantageous that the cut can be simulatedas often as desired without destroying the original recording of thecutting location taken into consideration. Therefore, it is no longerrequired to make protective copies before the cutting editing in casethat a cut is made erroneously.

Drawing

Exemplified embodiments of the invention are illustrated in the drawingand are explained in more detail in the following description. Thedrawings show

FIG. 1 a-d schematically the time cycle of the video information, thesound information before and during the recording, as well as during theplayback in accordance with a first exemplified embodiment,

FIG. 2 a-d also schematically the time cycles in accordance with asecond exemplified embodiment of the invention.

Description of the Exemplified Embodiments

Line (a) of FIG. 1 schematically illustrates the cycle of the video datafor a picture sequence: n, n+1,n+2,n+3. Thereby, the illustratedsegments may represent either half pictures, full pictures orsubsegments of the same. The data flow is interrupted in thetransmission area V between the half or full pictures of the subsegmentsof the same which, for example, corresonds to the V-gap in the videosignal.

Sound data segments are formed of the continuous sound data belonging tothe video data, whose repeat frequency corresponds to the video datasegments. However, in accordance with the invention the amount of thesound data belonging to a video data segment also includes sound datawhich belong to a preceding video segment and such sound data whichbelong to a subsequent video data segment. Consequently an overlappingof the sound data to be recorded occur and thereby a double recording inthe overlapping segment. Subsequently, the sound data segments t,t_(n+1), t_(n+2),t_(n+3) are time compressed, with generally knowndigital storage devices, in such a manner that the sound informationincluding the information ranges from the preceding and the followingvideo data segment belonging to one video data segment are recordedwithin the cycle which also corresponds to the video data segment. Thesetime compressed sound data segments are indicated in line (b) FIG. 1 ast'_(n),t'_(n+1),t'_(n+2), and t'_(n+3).

In this form the sound data segments can be recorded onto a magnetictape by means of one channel, that is, with one single circuit. In thisform they are also cutable in a simple manner: During the transmissionfrom one video scene to the following a sound data can be placed harshlyon top of each other at the cutting location. During the gating out ofthe old sound information no Read-Modify-Write cycle must be passed,because a soft changeover is performed automatically during backplay.The sound data segments are again time expanded to the original timeperiod during the backplay in accordance with line c of FIG. 1, so thatthe overlap in range T. The dotted line represents sound data segmentsin accordance with line (c) of FIG. 1 for ones of index n, n+2,n+4,etc., while the full line represent the segments of index n+1,n+3,n+5etc. The sound data recorded in the overlapping range T are alsocontained in successive segments. Sound signal segments are changedduring the backplay by using digital multiplication circuits inconjunction with a ramp generator in the overlapping range T in such amanner that the multiplication factor changes on the output of eachmultiplication circuit for the duration of time T from a maximum to aminimum or vice versa. Therefore, the multiplication factor for thesignal of the outgoing sound segment changes in the time T between thevalue 1.0 to 0.0 and the multiplication factor for the incoming soundsignal in the time T between the values 0.0 and 1.0. For an availablesound information corresponding to line (c) of FIG. 1, a changeoverprocess between identical data occurs constantly during time T duringthe continuous operation in accordance with (d). Due to this changeoverbetween identical sound information the changeover is not recognizeablein the signal: The undisturbed sound signal is transmitted.

When adding an actual television scene to an already earlier recordedtelevision scene by means of a harsh cut the time compressed recordedsound data are also harshly cut. Due to the corresponding base delays inthe video signal and the continuous changeover of the sound segmentsduring playback it is accomplished that the sound data of the outgoingtelevision scene are maintained beyond the cut time point for theduration of the half changeover interval T. Analogous thereto, the sounddata of the new video scene are contained, for the time of the halfchangeover duration T before the start of the video data recording, inthe recorded sound signal. The changeover is performed interference freeduring the transmission from the one sound performance to the followingby means of a changeover process according to FIG. 1 (d), in particularwithout any undesirable sudden sound amplification changes.

The recording and backplay of a sound performance belonging to a definedvideo signal, which is divided into segments, is performed in theexemplified embodiment of FIG. 2 principally in the same manner as inexemplified embodiment of FIG. 1, however, the changeover intervals Tare so selected that they run in a timely sequence without anyinterruption. Therefore, the sound data segments include not only thesound data belonging to the actual video data segment, but also the halfof the sound data of the preceding video data segment and also half ofthe sound data of the subsequent video data segment. Therefore, inaccordance with FIG. 2(c) the sound data are doubly recorded. Thus, agreat safety against data loss is obtained because of the 100%redundancy, without using complex error protective measures. During thebackplay of such recorded sound data a continuous changeover process isperformed for the duration of the changeover intervals T in the samemanner as for FIG. 1(d), described in FIG. 2 (d). However, since thesechangeover intervals T are succesively arranged without any joints acontinuous changeover occurs. This technology results in the continuousvideo scene in an interference free sound signal, during the changeoverfrom one sound performance to the next in a sufficiently largechangeover interval, so that interfering sound amplification changes areeliminated and finally it permits the reconstruction of the scanningvalues from the preceding and subsequent sound data segment in case of adata loss of a sound data segment.

What is claimed is:
 1. A process for storing a plurality of digitallycoded sound signals that are synchronous with video signals, the processcomprising steps of:providing a plurality of successive sound datasignal segments associated with a successive plurality of video datasignal segments, each of the sound data signal segments being digitallycoded with sound data synchronously associated with a time cycle of arespective one of the video data signal segments, the video data signalsegments constituting a plurality of immediately preceding andsucceeding video data segments relative to each other, the sound dataassociated with the video data segments constituting a first and secondhalf of the sound data; time compressing the sound data; and editinginto a time period corresponding to the time cycle of the respective oneof the video data signal segments, a reproduction of a second half ofthe time compressed sound data associated with the immediately precedingvideo data signal segment and a reproduction of a first half of the timecompressed sound data associated with the immediately succeeding videodata signal segment in addition to the time compressed sound datasynchronously associated with the respective one video data signalsegment so as to store a 100% redundancy of the sound data during thetime period.
 2. The process in accordance with claim 1, wherein theedited time period corresponds to the time cycle of one video datasignal segment representing a half video frame.
 3. The process inaccordance with claim 1, wherein the edited time period corresponds tothe time cycle of one video data signal segment representing a fullvideo frame.
 4. The process in accordance with claim 1, wherein theediting includes editing the time compressed sound data signal segmentsat a predetermined editing location during a transmission from one videodata signal segment to an immediately succeeding video data signalsegment by placing sound data on top of each other at the predeterminedediting location to thereby overlap identical data segments.
 5. Aprocess for storing and reproducing a plurality of digitally coded soundsignals that are synchronous with video signals, the process comprisingsteps of:providing a plurality of successive sound data signal segmentsassociated with a successive plurality of video data signal segments,each of the sound data signal segments being digitally coded with sounddata synchronously associated with a time cycle of a respective one ofthe video data signal segments, the video data signal segmentsconstituting a plurality of immediately preceding and succeeding videodata segments relative to each other, the sound data associated with thevideo data segments constituting a first and second half of the sounddata; time compressing the sound data; editing into a time periodcorresonding to the time cycle of the respective one of the video datasignal segments, a reproduction of a second half of the time compressedsound data associated with the immediately preceding video data signalsegment and a reproduction of a first half of the time compressed sounddata associated with the immediately succeeding video data signalsegment in addition to the time compressed sound data synchronouslyassociated with the respective one video data signal segment so as tostore a 100% redundancy of the sound data during the time period, thestoring producing overlaps of the successive sound signals; backplayingthe time compressed sound signal segments; and changing the timecompressed sound signal segments during the backplaying so that a signalof an outgoing time compressed sound signal segment changes from amaximum to a minimum value and an incoming time compressed sound signalsegment changes from a minimum to a maximum value so as to effect achangeover interval between idential sound data which were timecompressed for adjacent time cycles.
 6. A process for storing andreproducing a plurality of digitally coded sound signals that aresynchronous with video signals, the process comprising stepsof:providing a plurality of successive sound data signal segmentsassociated with a successive plurality of video data signal segments,each of the sound data signal segments being digitally coded with sounddata synchronously associated with a time cycle of a respective one ofthe video data signal segments, the video data signal segmentsconstituting a plurality of immediately preceding and succeeding videodata segments relative to each other, the sound data associated with thevideo data segments constituting a first and second half of the sounddata; time compressing the sound data; editing into a time periodcorresponding to the time cycle of the respective one of the video datasignal segments, a reproduction of a second half of the time compressedsound data associated with the immediately preceding video data signalsegment and a reproduction of a first half of the time compressed sounddata associated with the immediately succeeding video data signalsegment in addition to the time compressed sound data synchronouslyassociated with the respective one video data signal segment so as tostore a 100% redundancy of the sound data during the time period;backplaying the time compressed sound signal data segments; and timeexpanding the sound data signal segments during the backplaying.